Disable AWS SES retry mechanism

If it is a hard bounce, SES will not retry sending the email and you'll receive feedback as soon as the hard bounce occurs. If it's a soft bounce (i.e. due to a transient issue), then SES will retry sending the message. This cannot be disabled. For more info on hard bounces vs. soft bounces, please check these articles:

• https://aws.amazon.com/premiumsupport/knowledge-center/ses-understand-soft-bounces/
• https://aws.amazon.com/premiumsupport/knowledge-center/ses-high-bounce-rate/